Aircraft Propulsion Geartrain for Selective Thrust and Lift Power Split

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Solution Overview

Problem

Existing aircraft propulsion systems lack the ability to efficiently alternate between generating power for multi-directional propulsion, such as horizontal thrust and vertical lift, leading to inefficiencies in maneuverability and power distribution.

Innovation Solution

Aircraft propulsion system with a dual propulsor configuration, including a ducted and an open rotor, powered by a gas turbine engine core and an electric machine, utilizing a geartrain and lock devices to selectively control the rotation of propulsors, allowing independent operation in horizontal and vertical modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single propulsion system is used for both horizontal and vertical flight, then the system structure is simplified, but the propulsion efficiency decreases

Engineering Contradiction:
Improvepropulsion system structureVSAvoidpropulsion efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The propulsion system is segmented into two independent propulsors: a ducted rotor for horizontal thrust and an open rotor for vertical lift. This segmentation allows each propulsor to be optimized for its specific function, resolving the contradiction between system simplicity and propulsion efficiency by eliminating the need for a single compromise design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically switches between different propulsion modes by independently controlling the two propulsors. During horizontal flight, only the ducted rotor operates; during vertical flight, only the open rotor operates. This dynamic operation optimizes propulsion efficiency for each flight phase while maintaining overall system manageability.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If power is distributed to both propulsors simultaneously, then the system has more flexibility, but the power distribution control becomes complex

Engineering Contradiction:
Improveflight mode flexibilityVSAvoidpower distribution control
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The power distribution system dynamically engages or disengages specific propulsors based on flight mode requirements. The engagement mechanism allows the system to activate only the necessary propulsor for the current operation, providing flight mode flexibility while simplifying power distribution control by avoiding simultaneous operation of both propulsors.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control system automatically selects which propulsor to engage based on flight conditions, reducing the complexity of manual power distribution control. The system self-regulates power allocation to the appropriate propulsor without requiring complex external control inputs.

Inventive Principle:
Principle #25Self-service

3Productivity

If the second propulsor is stopped during vertical operations, then the horizontal thrust is reduced, but the vertical lift efficiency is improved

Engineering Contradiction:
Improvevertical lift efficiencyVSAvoidhorizontal thrust
Core Design Contradiction:
ProductivityVSForce

Solution Approach 1:

The system extracts and isolates the vertical lift function to a dedicated open rotor propulsor, separating it from the horizontal thrust function. During vertical operations, the ducted rotor (horizontal thrust source) is stopped or disengaged, allowing the open rotor to operate independently for vertical lift without the interference of horizontal thrust generation, thereby improving vertical lift efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables efficient power distribution for both horizontal thrust and vertical lift, optimizing propulsion for various flight maneuvers by reducing horizontal thrust during vertical operations and enhancing power transmission to the vertical propulsor.

Implementation Method 1

a gas turbine engine core (26) configured to rotate the rotating structure at a first rotational speed during a first mode and at a second rotational speed during a second mode

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 2

an electric machine configured to drive rotation of a component about the centerline axis down to a zero rotational speed

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 3

The first propulsor rotor may be configured to generate propulsive force in a first direction. The second propulsor rotor may be configured to generate propulsive force in a second direction that is different than the first direction

Methodology Applied
Scientific EffectAerodynamic propulsion: Aerofoil

Data Source

PatentEP4283106B1Selective power distribution for an aircraft propulsion system
Publication Date: 2025.11.12 RTX CORP
  • EP4283106B1 patent drawingFigure 1
  • EP4283106B1 patent drawingFigure 2
  • EP4283106B1 patent drawingFigure 3

AI summary

An assembly (20) is provided for an aircraft. The aircraft assembly (20) includes a rotating structure (68), a geartrain (78), a propulsor rotor (24) and an electric machine (80). The rotating structure (68) includes a turbine rotor (60). The geartrain (78) includes a sun gear (92), a ring gear (94), a plurality of intermediate gears (96) and a carrier (98). The sun gear (92) is rotatably driven by the rotating structure (68). Each of the intermediate gears (96) is between and meshed with the sun gear (92) and the ring gear (94). Each of the intermediate gears (96) is rotatably mounted to the carrier (98). The propulsor rotor (24) is rotatably driven by the carrier (98). The electric machine (80) is coupled to the ring gear (94).